Conduit assembly and method of use thereof

ABSTRACT

A conduit assembly for supporting a cover of a maintenance structure with a passage therein. The conduit assembly includes one or more conduit segments. Each conduit segment has at least one aperture, an also includes top and bottom surfaces adapted to be positioned adjacent to bottom and top surfaces respectively of other conduit segments to form a conduit structure having a conduit passage therein alignable with the passage. The conduit structure has an inner wall surface defining the conduit passage and an opposed outer wall surface adapted to receive a coating of mortar. The conduit assembly also includes one or more shims for positioning on the top surface of the conduit segment, for locating the cover substantially at a predetermined position therefor.

FIELD OF THE INVENTION

This invention is related to conduit assemblies for supporting coversfor maintenance structures.

BACKGROUND OF THE INVENTION

Maintenance structures, such as manhole structures or storm sewerbasins, are typically included in modern streets. For each maintenancestructure, a cover is required, usually in the form of a removable lidor grating mounted in a frame. However, the cover is required to belocated at a predetermined position. This is necessary in order toposition the cover properly relative to a street or road surfacesurrounding it. Typically, the surrounding road surface is an asphaltsurface which is the top of a final coat of asphalt, but the cover mayalso be positioned in (or partially in) a curb or sidewalk. For example,a manhole cover is typically positioned so that a top surface of the lidportion is substantially flush with the surrounding road surface.

In practice, locating a maintenance structure so that the cover thereforis at the predetermined position is difficult, because maintenancestructures are relatively large, and making adjustments in the positionof a typical maintenance structure to the accuracy required inpositioning the cover is very difficult. In the prior art, where themaintenance structure is lower than it should be in accordance with aplan, the mispositioning of the maintenance structure is usuallyaddressed by using one or more risers, interposed between themaintenance structure and the cover, to support the cover at the desiredelevation. For example, U.S. Pat. No. 4,121,390 (Hall et al.) disclosesthe use of precast concrete units positioned on the maintenancestructure to support the cover. Also, U.S. Pat. No. 6,169,760 (Sinclair)discloses an adjustment riser molded to include ribs (in top surfaces)and corresponding grooves (in lower surfaces). However, the prior artrisers do not include an apparatus to facilitate height adjustmentswhich are less than a single riser's thickness.

Therefore, there is a need for a conduit assembly which will permitfiner adjustment of the position of the cover relative to themaintenance structure.

SUMMARY OF THE INVENTION

In its broad aspect, the invention provides a conduit assembly forsupporting a cover of a maintenance structure with a passage therein.The conduit assembly includes one or more conduit segments. Each conduitsegment has at least one aperture, and also includes top and bottomsurfaces adapted to be positioned adjacent to bottom and top surfacesrespectively of other conduit segments to form a conduit structurehaving a conduit passage therein alignable with the passage. The conduitstructure has an inner wall surface defining the conduit passage and anopposed outer wall surface adapted to receive a coating of mortar. Theconduit assembly also includes one or more shims for positioning on thetop surface of the conduit segment, for locating the cover substantiallyat a predetermined position therefor.

In another aspect, the invention provides two or more cavities in thebottom surface of each conduit segment for facilitating movement of eachconduit segment.

In yet another of its aspects, the top surface of each conduit segmentincludes one or more channels in which the shims are receivable, formaintaining each shim in a preselected position relative to the topsurface.

In yet another aspect, the conduit assembly is made of high-densitypolyethylene.

In another aspect, one or more conduit segments includes a body with amain portion and one or more detachable portions adapted for removalfrom the main portion. Removal of a detachable portion results in anopening in the conduit structure extending between the outer wallsurface and the inner wall surface of the conduit structure. The conduitassembly also includes one or more pipe segments, each having an innerend and an outer end. The inner end is receivable in the opening in theconduit structure, and the outer end is positionable a predetermineddistance outside the conduit structure to provide for drainage throughthe pipe segment into the conduit passage.

In yet another aspect, the invention provides one or more ladder rungspositioned for location in the conduit passage.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood with reference to the drawings,in which:

FIG. 1A is a side view of a preferred embodiment of a conduit assemblyof the invention including one or more shims, the conduit assembly beingpositioned on a maintenance structure and supporting a cover for themaintenance structure;

FIG. 1B is a top view of the conduit assembly of FIG. 1A positioned onthe maintenance structure, and the cover located on the conduitassembly;

FIG. 1C is a cross-section of the conduit assembly of FIGS. 1A and 1B,drawn along line 1C-1C in FIG. 1B;

FIG. 2A is a top view of a preferred embodiment of a conduit segment ofthe invention with shims positioned thereon;

FIG. 2B is a top view of an alternative embodiment of a conduit segmentof the invention having channels on the top surface and shims positionedtherein;

FIG. 3 is a cross-section of the conduit segment and shims of FIG. 1Btaken along line 3-3 in FIG. 2B;

FIG. 4 is a bottom view of a preferred embodiment of the conduitsegment;

FIG. 5 is a cross-section taken along line 5-5 in FIG. 4;

FIG. 6 is a cross-section of two adjacent conduit segments of theconduit assembly of FIGS. 1A-1C, showing the manner in which the conduitsegments cooperate with each other;

FIG. 6A is a side view of an alternative embodiment of a conduitassembly of the invention, positioned on a maintenance structure andsupporting a cover for the maintenance structure;

FIG. 6B is a cross-section of the conduit assembly, maintenancestructure, and cover of FIG. 6A;

FIG. 7 is a top view of another alternative embodiment of the conduitsegment of the invention;

FIG. 8 is a cross-section taken along line 8-8 in FIG. 7;

FIG. 9 is a top view of another alternative embodiment of the conduitsegment of the invention;

FIG. 10 is a cross-section taken along line 10-10 in FIG. 9;

FIG. 11 is a bottom view of the conduit segment of FIG. 9;

FIG. 12 is a cross-section taken along line 12-12 in FIG. 11;

FIG. 13A is a side view of another alternative embodiment of the conduitassembly of the invention interposed between a maintenance structure anda cover therefor;

FIG. 13B is a bottom view of a conduit segment in the conduit assemblyof FIG. 13A, the conduit segment having a detachable portion;

FIG. 13C is a top view of the conduit segment of FIG. 13B;

FIG. 13D is a cross-section of the conduit segment of FIGS. 13B and 13Ctaken along line 13D-13D in FIG. 13C;

FIG. 14 is a top view of the maintenance structure, conduit assembly andcover of FIG. 13A;

FIG. 15 is a cross-section taken along line 15-15 in FIG. 14; and

FIG. 16 is a top view of an alternative embodiment of a conduit segmentof the invention with detachable portions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Reference is first made to FIGS. 1A-1C, 2A, 2B, 3, and 4 to describe apreferred embodiment of a conduit assembly in accordance with theinvention indicated generally by the numeral 20. The conduit assembly 20is for supporting a cover 22 of a maintenance structure 24 with apassage 26 therein. As can be seen in FIGS. 1A and 1C, the conduitassembly 20 includes one or more conduit segments 28, each of which hasan aperture 30 (FIG. 2A), as will be described. Each conduit segment 28has a top surface 32 (FIG. 2A) which is adapted to be positioned facingupwardly, and a bottom surface 34 (FIG. 4) positioned opposite to thetop surface 32 and adapted to be positioned facing downwardly. The topsurface 32 and the bottom surface 34 are adapted to cooperate withbottom and top surfaces respectively of adjacent conduit segments sothat adjacent conduit segments are maintained in position relative toeach other to form a conduit structure 36 having a conduit passage 38therein, as will be described. As can be seen in FIG. 1C, the conduitpassage 38 is alignable with the passage 26. The conduit structure 36has an inner wall surface 40 and an opposed outer wall surface 42 whichis adapted to receive a coating of mortar (not shown). Also, thepreferred embodiment of the conduit assembly 20 includes one or moreshims 44 to be positioned on the top surface 32 of the conduit segment28, for locating the cover 22 substantially at a predetermined positiontherefor.

In the preferred embodiment, each conduit segment 28 includes two ormore cavities 46 in the bottom surface 34 thereof (FIGS. 4-5). Thecavities 46 facilitate movement of the conduit segment 28, as will bedescribed. Each conduit segment 28 includes an interior wall 45 definingthe aperture 30 and an exterior wall 47 defining the outer edge of theconduit segment 28. The interior walls 45 of the conduit segments 28which are included in the conduit structure 36 collectively form theinner wall surface 40 of the conduit structure to define the conduitpassage 38. Also, the exterior walls 47 of the conduit segments in theconduit structure 36 collectively form the outer wall surface 42 of theconduit structure 36.

Also, the top surface 32 of each conduit segment 28 preferably includesone or more channels 48 (FIGS. 2B-3) in which shims 44 are receivable.The channel 48 serves to help maintain the shim 44 in a preselectedposition relative to the top surface 32. In the absence of the channels48, the shims may tend to move on the top surface 32 during installationof the shims 44, as will be described.

The conduit segments 28 and the shims 44 can be made of any suitablematerial. Preferably, the conduit segments 28 and the shims 44 are madeof a relatively tough, light-weight plastic, so that they are tough anddurable, and relatively easy to handle. In the preferred embodiment, theconduit segments 28 and the shims 44 are made of high-densitypolyethylene.

Preferably, the conduit segments 28 are produced with variousthicknesses. For example, each conduit segment 28 can have a thicknessof about 12 mm. (0.47 in.), 25 mm. (0.98 in.), or 50 mm. (1.97 in.).Also, the width and other dimensions of the conduit segments can vary asrequired. In a conduit assembly, conduit segments having differentthicknesses may be used as required. Also, conduit segments havinggreater thickness can be used for specific applications, as will bedescribed.

As can be seen in FIGS. 2A, 2B and 4, the top surface 32 preferablyincludes a mating portion 50 with a series of alternating peaks 52 andvalleys 54. The bottom surface 34 also includes a mating portion 56 withalternating peaks 58 and valleys 60. The mating portions 50 and 56 arepositioned relative to each other so that the mating portion 56 on thebottom surface 34 of a first conduit segment cooperates with the matingportion 50 on the top surface 32 of a second conduit segment which ispositioned immediately below the first conduit segment. The matingportions 50, 56 cooperate with each other because the peaks 52 fit intothe valleys 60 and the peaks 58 fit into the valleys 54 (FIG. 6). Itwill be appreciated by those skilled in the art that a variety ofcooperating means could be used. In the preferred embodiment, a“sawtooth” design (FIG. 6) is used in which the peaks and valleys arerelatively sharply defined. Preferably, the distance from a peak to anadjacent valley is between approximately 3 mm. (0.12 in.) toapproximately 4 mm. (0.16 in.). This design is advantageous due tosimplicity of manufacturing.

In use, after the maintenance structure 24 is put in position, one ormore conduit segments 28 is positioned on the maintenance structure 24.The apertures 30 in the conduit segments 28 are aligned with the passage26 in the maintenance structure 24 as the conduit segments 28 are put inplace. The first conduit segment 28 to be emplaced is positioneddirectly on the maintenance structure 24, with the bottom surface 34 ofthe conduit segment 28 engaging the maintenance structure 24. In somecircumstances, only one conduit segment 28 may be sufficient, dependingon the predetermined position of the cover 22 relative to the actualposition of the maintenance structure 24, and the actual position of thecover 22, if it is placed directly on the maintenance structure 24. Ifany additional conduit segments 28 are needed, they are put in positionby first aligning the bottom surface 34 of the next conduit segment 28to be added to the stack with the top surface 32 of the next adjacent(and lower) conduit segment 28 so that the bottom surface 34 of thehigher conduit segment 28 cooperates with the top surface 32 of thelower conduit segment 28 to form a relatively stable conduit structure36. Once sufficient conduit segments 28 are in position, the cover 22 isemplaced on top of the conduit structure 36, to determine the extent towhich the cover 22 is or is not (as the case may be) located in thepredetermined position therefor. The cover 22 is placed directly on thetop surface 32 of the topmost conduit segment 28 in the conduitstructure 36. Shims 44 are preferably interposed between the top surface32 of the topmost conduit segment 28 and the cover 22, as required inorder to locate the cover 22 in the predetermined position therefor.

Preferably, the conduit segments 28 are put in place by way of manuallabour, in which the cavities 46 on the bottom surfaces 34 of theconduit segments 28 are utilized, in order to ensure that fingers ofworkers are not crushed between adjacent conduit segments 28 as theconduit structure 36 is erected.

It will be understood that, as is known in the art, mortar is to beplaced on the outer wall surface 42 after the conduit assembly 20 isconstructed and the cover 22 has been positioned thereon. Any gapsbetween the top of the topmost conduit segment 28, on the one hand, andthe bottom of the lowest conduit segment 28 and the maintenancestructure 24, on the other hand, are to be filled in with mortar,applied from outside the conduit assembly 20. In this way, the conduitpassage 38 will be made substantially watertight.

In the preferred embodiment, the top surfaces 32 of the conduit segments28 include channels 48 in which the shims 44 are receivable. The shims44 can then be pushed into the channels 48 on the top surface 32 of thetopmost conduit segment 28 when the shims 44 are interposed between thetopmost conduit segment 28 and the cover 22. The channels 48 serve tomaintain the shims 44 in position. Preferably, the shims 44 are providedin a variety of preselected sizes and shapes, so that a shim 44 havingthe appropriate size can be selected to be interposed.

In the preferred embodiment, and as shown in FIG. 2B, the channels 48 donot extend through to the interior wall 45 of the conduit segment 28.The inner wall surface 40, which is formed by the interior walls 45 ofthe conduit segments 28 in the conduit structure 36, is preferablysubstantially smooth and generally watertight. As noted above, theexterior of the conduit structure 36 also preferably is to be coatedwith mortar to assist in preventing groundwater from entering into theconduit passage 38.

Additional embodiments of the invention are shown in FIGS. 6A, 6B, and7-16. In FIGS. 6A, 5B, and 7-16, elements are numbered so as tocorrespond to like elements shown in FIGS. 1A, 1B, 1C, 2A, 2B, 3, 4, and5.

An alternative embodiment of a conduit assembly 120 is shown in FIGS. 6Aand 6B positioned on the maintenance structure 24 and supporting thecover 22. In the conduit assembly 120, conduit segments 28 form theconduit structure 36. No shims are included in the conduit assembly,however.

Another alternative embodiment of a conduit segment 228 is shown inFIGS. 7 and 8. The conduit segment 228 includes a ladder rung 262 havinga body 264 with arms 266, 268 extending from the body 264, eachextending in substantially the same direction. The arms 266, 268 aremounted into the interior wall 245 of the conduit segment 228, as shownin FIGS. 7 and 8. Preferably, the conduit segments 228 are spaced apartfrom each other by conduit segments 28 which do not have the ladderrungs mounted therein, as a conduit structure is constructed of theconduit segments 228 and shims, as needed. The ladder rungs 262 are thusspaced apart vertically so that they can be conveniently used by aworker (not shown) as a means of ingress and egress to the passage 26 inthe maintenance structure 24.

Preferably, the conduit segment 228 has sufficient thickness that theladder rung 262, when supporting a load (not shown), can itself besupported by the conduit segment 228. In practice, it has been foundthat the conduit segment 228 should preferably have a thickness of about75 mm. (2.95 in.) or more, to ensure that the conduit segment 228 cansupport the weight of a man on the rung 262.

Another alternative embodiment of the conduit segment 328 is shown inFIGS. 9-12. As can be seen in FIGS. 9 and 11, an aperture 330 in theconduit segment 328 is substantially square. The conduit segment 328 ismade up of four body portions 329 which are joined to each other atright angles to form a square. As can be seen in FIG. 9, a top surface332 includes mating portions 350 separated by channels 348. FIG. 11shows a bottom surface 334 which includes mating portions 356.Preferably, cavities 346 are positioned in substantially the middle ofeach body portion 329.

As can be seen in FIGS. 9 and 10, shims 344 are positioned in thechannels 348. Preferably, the shims 344 are positioned in the topmostconduit segment 328 in a conduit structure, as required.

Another alternative embodiment of a conduit assembly 420 is shown inFIGS. 13A-16. The conduit assembly 420 includes one or more conduitsegments 427. As can be seen in FIGS. 13A and 15, the conduit assembly420 can also include one or more conduit segments 428. Preferably, theconduit segment 428 is one of the standard sizes (e.g., 12 mm. (0.47in.), 25 mm. (0.98 in.), or 50 mm. (1.97 in.) thickness.) In FIGS. 13Aand 15, the conduit segment 427 is shown positioned on the maintenancestructure 24, and the conduit segment 428 is positioned on top of theconduit segment 427. It will be appreciated by those skilled in the artthat the conduit segment 427 need not be positioned directly on top ofthe maintenance structure 24. The relative positioning of the conduitsegments 428 and the conduit segment 427 is determined based onconvenience. Also, any number of conduit segments 428 can be used withany number of conduit segments 427, as required.

Each conduit segment 427 includes a body 471 and a main portion 472 ofthe body 471. Each conduit segment 427 includes one or more detachableportions 474 adapted for removal from the main portion 472. Removal ofthe detachable portion 474 from the main portion 472 creates an opening476 between an interior wall 445 of the conduit segment 427 and anexterior wall 447 located opposite the inner wall surface 445. Theopening 476 is adapted for receiving at least part of a pipe segment478. Although slots for receiving shims are not shown in FIG. 13C, itwill be appreciated by those skilled in the art that the conduit segment427 could include such slots.

As can be seen in FIG. 15, a top surface 484 of the cover 22 ispositioned at a final design grade, i.e., level with a surface 486 of afinal layer 487 of asphalt (or other finishing material) which is to belaid down. However, a first lift 488 of asphalt (or other finishingmaterial) is usually laid down shortly after installation of themaintenance structure 24, the conduit assembly 420, and the cover 22.The first lift 488 has a surface 489 generally positioned substantiallybelow the final design surface 486 (FIG. 15). As is known in the art,the asphalt is usually laid down in two (or more) lifts, approximatelyone year (or more) apart, in order to allow the street material (and themaintenance structure) 24 to subside, or settle, before the final liftof asphalt 487 is laid down. However, because the cover 22 is positionedaccording to the design of the completed road, the surface 484 of thecover 22 is at the elevation of the surface 486 of the second lift ofasphalt 487. Therefore, and as shown in FIG. 15, until the second liftof asphalt 487 is laid down, water runoff on the surface 489 of thesurrounding asphalt 488 will not drain into the cover 22.

Accordingly, the pipe segment 478 is required to provide for drainage ofwater on the surface 489 into the maintenance structure 24, until thesubsequent asphalt layer(s) result in the surface 486 at the finaldesign elevation. When the second lift of asphalt is to be laid down,the pipe segment 478 is filled (usually with cement), and then coveredby the second lift.

Preferably, the conduit segment 427 is approximately 75 mm. (2.95 in.)thick. This thickness permits the detachable portion 474 to have adiameter sufficiently large to receive a 2¼″ pipe, or in any event apipe large enough to drain water from the surface 489 reasonablyquickly.

As can be seen in FIG. 15, as the pipe segment 478 is put into position,an upper end 480 is spaced laterally apart from the cover 22. Also, alower end 482 is positioned in communication with a conduit passage 438in a conduit structure 436 formed by the stacked conduit segments 427,428. Although the pipe segment 478 is shown as having a 90° elbow, itwill be appreciated by those skilled in the art that the pipe segment478 could have a variety of configurations.

The conduit structure 436 defines the conduit passage 438 which issubstantially square in plan view. However, it will be appreciated bythose skilled in the art that the conduit segments including detachableportions can be provided in a variety of forms. For example, a conduitsegment 527 is shown in FIG. 16 which is substantially round in planview. The conduit segment 527 includes detachable portions 574, similarto detachable portions 474 in the conduit segment 427.

It will be appreciated by those skilled in the art that the inventioncan take many forms, and that such forms are within the scope of theinvention as claimed. Therefore, the spirit and scope of the appendedclaims should not be limited to the descriptions of the preferredversions contained herein.

1. A conduit assembly for supporting a cover of a maintenance structurewith a passage therein, the conduit assembly comprising: a plurality ofconduit segments, each said conduit segment having at least oneaperture; each said conduit segment having a top surface adapted to bepositioned facing upwardly and a bottom surface positioned opposite tothe top surface and adapted to be positioned facing downwardly, said topsurface and said bottom surface being adapted to cooperate with bottomand top surfaces respectively of adjacent conduit segments such thatsaid adjacent conduit segments are maintained in position relative toeach other to form a conduit structure having a conduit passage therein,the conduit passage being alignable with the passage; the conduitstructure having an inner wall surface defining the conduit passage andan opposed outer wall surface adapted to receive a coating of mortar;and at least one shim to be positioned on the top surface of at leastone conduit segment, for locating the cover substantially at apredetermined position therefor.
 2. A conduit assembly according toclaim 1 in which each said conduit segment includes at least twocavities in the bottom surface thereof, for facilitating movement ofeach said conduit segment.
 3. A conduit assembly according to claim 1 inwhich the top surface of each said conduit segment includes at least onechannel in which said at least one shim is receivable, for maintainingsaid at least one shim in a preselected position relative to the topsurface.
 4. A conduit assembly according to claim 1 comprisinghigh-density polyethylene.
 5. A conduit assembly according to claim 1 inwhich at least one of said conduit segments includes: a body with a mainportion and at least one detachable portion adapted for removal fromsaid main portion, to result in an opening in the conduit structureextending between said outer wall surface and said inner wall surfacethereof; and the conduit assembly additionally including at least onepipe segment having an inner end and an outer end, the inner end beingreceivable in said opening in the conduit structure, and the outer endbeing positionable a predetermined distance outside the conduitstructure to provide for drainage through said at least one pipe segmentinto the conduit passage.
 6. A conduit assembly according to claim 1 inwhich each conduit segment includes at least one ladder rung positionedfor location in the conduit passage.
 7. A conduit assembly according toclaim 1 in which the conduit structure defines a conduit passage havingsubstantially a round cross-section.
 8. A conduit assembly according toclaim 1 in which the conduit structure defines a conduit passage havinga substantially square cross-section.
 9. A conduit assembly according toclaim 1 in which the conduit structure defines a conduit passage havinga substantially rectangular cross-section.
 10. A conduit assembly forsupporting a cover of a maintenance structure with a passage therein,the conduit assembly comprising: at least one conduit segment having atleast one aperture; said at least one conduit segment being positionableon the maintenance structure such that said at least one aperture issubstantially alignable with the passage; and at least one shim to bepositioned on the top surface of said at least one conduit segment, forlocating the cover substantially at a predetermined position therefor.11. A conduit assembly according to claim 10 in which said at least oneconduit segment includes at least two cavities in the bottom surfacethereof, for facilitating movement of said at least one conduit segment.12. A conduit assembly according to claim 10 in which the top surface ofsaid at least one conduit segment includes at least one channel in whichsaid at least one shim is receivable, for maintaining said at least oneshim in a preselected position relative to the top surface.
 13. Aconduit assembly according to claim 10 comprising high-densitypolyethylene.
 14. A conduit assembly according to claim 10 in which saidat least one conduit segment has an inner wall surface defining said atleast one aperture and an opposed outer wall surface adapted forreceiving a coating of mortar.
 15. A conduit segment for supporting acover of a maintenance structure, the maintenance structure having apassage therein, the conduit segment comprising: a body with at leastone aperture therein; the body having a top surface and a bottom surfacepositioned opposite to the top surface, the top and bottom surfacesbeing adapted to cooperate with bottom and top surfaces respectively ofadjacent conduit segments to form a conduit structure; and the topsurface being adapted for receiving at least one shim, to locate thecover substantially at a predetermined position.
 16. A conduit segmentaccording to claim 15 in which the body includes at least two cavitiesin the bottom surface thereof, for facilitating movement thereof.
 17. Aconduit segment according to claim 15 in which the top surface includesat least one channel for receiving said at least one shim, said at leastone channel being adapted to maintain said at least one shim in apreselected position relative to the top surface.
 18. A conduit segmentaccording to claim 15 comprising high-density polyethylene.
 19. Aconduit segment according to claim 15 in which the body includes a mainportion and at least one detachable portion adapted for removaltherefrom, to create an opening between an inner wall surface of theconduit segment defining said at least one aperture and an outer wallsurface located opposite the inner wall surface, for receiving at leastpart of at least one pipe segment.
 20. A method of locating a cover of amaintenance structure at a predetermined position, the maintenancestructure having a passage therein, the method comprising the steps of:(a) providing at least one conduit segment having at least one aperture;(b) positioning said at least one conduit segment on the maintenancestructure such that said at least one aperture is substantially alignedwith the passage in the maintenance structure, to form a conduitstructure defining a conduit passage therein substantially aligned withthe passage; (c) positioning the cover on the conduit structure; (d)providing at least one shim; and (e) interposing said at least one shimbetween said at least one conduit segment and the cover, for locatingthe cover at a predetermined position therefor.
 21. A method of locatinga cover of a maintenance structure at a predetermined position, themaintenance structure having a passage therein, the method comprisingthe steps of: (a) providing at least one conduit segment having at leastone aperture, said at least one conduit segment having a top surface anda bottom surface positioned opposite to the top surface, the top surfaceincluding at least one channel; (b) positioning said at least oneconduit segment on the maintenance structure such that said at least oneaperture is substantially aligned with the passage in the maintenancestructure, to form a conduit structure defining a conduit passagetherein substantially aligned with the passage; (c) positioning thecover on the conduit structure; (d) providing at least one shimreceivable in said at least one channel; and (e) interposing said atleast one shim between said at least one conduit segment and the cover,said at least one shim being received in said at least one channel, forlocating the cover substantially at a predetermined position therefor.